The present disclosure herein relates to methods of fabricating semiconductor devices, and more particularly, to methods of forming fine patterns of a semiconductor device to form the fine patterns with a fine pitch exceeding the resolution limit of a known exposure equipment by using a double patterning process.
In order to manufacture a higher integrated semiconductor device, it is necessary to make a pattern fine. The size of each device has to be formed as small as possible to integrate more devices in a certain area. In order to achieve the higher integration, it is necessary to miniaturize a pitch which is the sum of the width of each pattern and the distance between the patterns. With a rapid decrease in the design rule of a semiconductor device, there is a limit to forming a pattern with a fine pitch due to the resolution limit to a photolithography process of forming a pattern necessary to realize a semiconductor device. In particular, there is a limit to forming a desired pattern with a fine pitch due to the resolution limit to a photolithography process of forming a line and space pattern on a substrate.
In order to solve the resolution limit to the photolithography process, there was suggested a method of forming a fine hard mask pattern with a fine pitch in a double patterning process. In the method of forming a fine pattern in the double patterning process, however, there are disadvantages in terms of a complicated process and a processing cost, since a deposition process and an etching process are performed in an opening with a large aspect ratio and a narrow width. Moreover, it is difficult to form a film having no defect such as a void inside the opening, since a material for forming a fine mask pattern has to be deposited in the opening with the large aspect ratio and the narrow width.